1. Field of the Invention
The present invention relates to a corrugated pipe joint suitable for connecting and coupling in a watertight fashion two synthetic resin corrugated pipes whose outer circumferential surfaces are formed into a concave-convex corrugated shape.
2. Description of the Related Art
Conventionally, various types of corrugated pipe joints like one described above have been manufactured and used. These are generally classified into two types in terms of circumferential surface configuration; a joint whose main body is formed into a hollow cylinder without a concave-convex corrugation and a joint whose main body is provided with concave-convex corrugations corresponding to the concave-convex corrugations of pipe bodies to be connected to each other. In addition, the joints are also classified into two types in terms of body construction; a joint whose main body is formed into a hollow cylinder and a joint whose main body is formed into a bisected semi-cylindrical configuration.
For example, Japanese Patent Unexamined Publication No. Hei. 6-44334 disclose a known joint in which a joint main body is formed into a bisected semi-cylindrical configuration as with the latter construction and in which the configuration of the joint main body is formed into something like a concave-convex spiral shape corresponding to the concave-convex spiral corrugations of pipe bodies that are to be connected together.
In the joint for corrugated spiral pipes disclosed in the publication, a seal member is prepared separately from the joint main body which is externally formed into substantially a concave-convex spiral configuration which coincides with the concave-convex spiral configuration of the joint main body and is internally formed into a concave-convex spiral configuration which corresponds to the concave-convex spiral corrugations of the pipes to be connected together. The seal member is then fitted in the joint main body. The joint main bodies each incorporating therein the seal member are then disposed on a portion where the two pipes are connected end-to-end to each other from above and below, respectively, so as to cover the butted portion and thereafter the joint main bodies are secured to each other by tightening respective confronting projecting edges thereof together with tightening bolts and nuts via bolt holes formed in the projecting edges.
With the conventional corrugated pipe joint, however, as described above, the joint main body is substantially formed into the concave-convex spiral configuration, the seal member is prepared which comprises the concave-convex spiral external configuration coinciding with the concave-convex spiral configuration of the joint main body and the concave-convex spiral internal configuration coinciding with the concave-convex spiral configuration of the pipe bodies to be connected together, and these joint main bodies and seal members are prepared in a pair, respectively and are then disposed so as to confront each other for use. Due to this construction it is found difficult to tightly pressure contact and join confronting concave-convex corrugated edges of the seal members along the full length thereof, and therefore there is caused a problem that a slight amount of water is liable to leak out or penetrate in through the pressure contact surfaces of the seal members. In addition, it is also difficult from a viewpoint of molding accuracy to join the seal members and the pipe bodies in a watertight fashion in such a manner as to maintain watertightness along the full circumference thereof in a circumferential direction, and therefore there is also caused a problem that it is difficult to securely prevent the leakage or penetration of a slight amount of water in the circumferential direction.
With a view to solving the problems inherent in the conventional known corrugated pipe joint assemblies described above, an object of the present invention is to provide a corrugated pipe joint which can securely maintain the watertightness between joint areas of joint main bodies and a watertight state in a circumferential direction to thereby eliminate any risk of leakage and penetration of water without a complicated construction.
To describe a construction provided by the present invention to attain the aforesaid object using reference numerals that are to be used in describing embodiments of the invention, there is provided a corrugated pipe joint comprising a joint main body 1 of a synthetic resin comprising in turn tightening projecting edges 12, 12 projecting outwardly from the circumferential end portions of an arc-like portion 11 in a radial direction and a watertightness-implementing packing 2 of an elastic material comprising in turn flange edges 22, 22 projecting outwardly from the circumferentially end portions of an arc-like portion 21 in the radial direction wherein engagement projections 17, 17 are formed on an inner circumferential surface of each of axial end portions b, b of the joint main body for mesh engagement with a root portion of a corrugated pipe, wherein elongated projections 14 and tightening bolt holes 16 are formed in a surface side of the projecting edges 12, 12, the elongated projections 14 being formed in such a manner as to-extend along an axial direction of the joint main body, the tightening bolt holes 16 being formed outwardly of the elongated projections 14, wherein depressed grooves 24 are formed in a back side of the flange edges 22, 22 in such a manner as to extend along the axial direction for the elongated projections 14 on the joint main body 1 to fit therein, and wherein a surface-side portion of the depressed groove 24 projects an appropriate thickness o toward the surface side beyond the surface of the projecting edge 12, 12 on the joint main body 1.
In addition, the above-mentioned object can also be achieved by a corrugated pipe joint for coupling corrugated pipes, according to the present invention, includes at least two joint components. Each of the joint components comprises a joint main body (1) made of a synthetic resin and a watertightness-implementing packing (2) made of an elastic material and assembled with the joint main body (1). The joint main body (1) includes an arc-shaped portion (11) and tightening projecting edges (12, 12) which are outwardly projected from the circumferential end portions of the arc-shaped portion (11) in a radial direction of the corrugated pipes to be coupled. Engagement projections (17), (17) are formed on an inner circumferential surface of each of the axial end portions so as to be engageable with a root portion of one of the corrugated pipes. Axially elongated projections (14) and tightening bolt holes (16, 16) are formed on each of the tightening projecting edges (12, 12). The watertightness-implementing packing (2) includes an arc-shaped portion (21) and flange edges (22), (22) projecting from the circumferentially end portions of the arc-like portion (21) in the radial direction. Axially extending depressed grooves (24) are formed in back sides of flange edges (22, 22) so ads to be fittingly engageable with the elongated projections (14) on the joint main body (1) respectively. Further, when the at least two joint components are coupled with one another, a surface portion of the flange edge which is disposed at a front side opposed to the depressed groove and is disposed closest to the adjacent joint component is closer to the adjacent joint component by a predetermined distance than a surface portion of the projecting edge of the joint main body which is closest to the adjacent joint component.
In embodying the corrugated pipe joint constructed as described above, the joint main body 1 is formed into a bisected half semi-circular arc-like body and the respective bisected semi-circular arc-like portions 11 are embodied as being formed slightly smaller than the semi-circle. Alternatively, the joint main body 1 may be embodied as a trisected circular body which is formed slightly smaller than one third of a circle. The joint main body 1 may be formed as a quadrisected body as required.
In addition, in a case where the concave-convex corrugations of corrugated pipes to be connected are spiral corrugations, the invention is carried out such that the engagement projections 17, 17 provided at the axial end portions b, b of the joint main body 1 are formed so as to follow the spiral direction so that they properly mesh with root portions of the corrugated spiral pipes, and on the contrary, in a case where corrugated pipes to be connected are concave-convex annular corrugated pipes, the invention is carried out such that the engagement projections are formed so as to follow the annular direction so that they properly mesh with root portions of the concave-convex annular corrugated pipes.
While there is no special limitation to synthetic resin for use for formation of the joint main body 1 of the invention, synthetic resins are preferable including polyolefin plastic such as polyethylene and polypropylene, thermoplastic rigid resin material such as polyvinyl chloride and FRP which is a resin material reinforced with glass fiber, and it is preferable in particular to select for use materials which are resistant to aging and superior in tensile load bearing capacity. In addition, not only natural and synthetic rubber but also an elastic flexible synthetic resin material can be used for the watertightness-implementing packing 2. In addition, the joint main body 1 and the watertightness-implementing packing 2 may be formed separately and thereafter bonded together as an integrated unit. As a mode for carrying out the invention, the joint main body 1 and the packing may be fitted together when in use.